Vacuum regulation for rectifiers.



' H. A. NEWCOMBJ VACUUM REGULATION FOR RECTIFIERS.

APPLICATION FILED FEBHSI 1915.

1,251,562. Patnted Jan. 1, 1918'.

WITNESSES: INVENTOR UNITED sTAnEs PATENT- OFFICE.

HAROLD -A. NEWCOHB, OF WILKINSIBUBG, PENNSYLVANIA, ASSIGNOB TO WESTING- HOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION 01' PENN-' SYLVANIA.

Specification of Letters Patent.

Patented Jan. 1, 1918.

Application filed February 3, 1915. Serial No. 5,889.

To all whom it may concern:

Be it known that I, HAROLD A. NEwcoMB, a citizen of the United States, and a resident of Wilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Vacuum Regulation for Rectifiers, of which the following is a specification.

My invention relates to vacuum electric apparatus, such, for example, as mercuryvapor rectifiers, and it has for its object to provide means and methods whereby the vacgum may be readily controlled in appa- By my invention, I am enabled to restore a proper degree of vacuum in a, tube which has failed in either of these ways, so that it will give many additional hours of service.

In the accompanying drawing, 1 is the container of a rectifier that is constructed of glass, quartz or similar material. anodes 2 and 3, constructed preferably of carbon or iron, are mounted in laterally extending arms 'at a considerable distance from each other in order to prevent short circuiting. A cathode 4 of mercury or other suitable conducting self-reconstructing mater atus dfth'emharacter s ecified. ----rial is placed in the lower portion of the con- The single figure o the accompanying drawing is a-di'agrammatic view of a mercury rectifier, with attendant circuits, ar-

after long service, the vacuum within thecontainer rises to such a high degree that the rectification becomes unstable. The resistance of the vapor path reaches an abnormally high figure and eventually the arc fails from one anode. The ensuing unilateral rectification, persisting for but a single wave in a rectifier maintained by a reactance coil but exhibited indefinitely when maintenance is by a direct current are, causes an unbalanced absorption of energy from the suppl stem with resultant voltage surges and liability of injury to the rectifier. This increase in the vacuum is apparently similar to the well known hardening of the vacuum in X-ray tubes. While I do not wish to be confined to any one theory for explaining this action, apparently the mall currentcarrying bodies and gas particles within the container are driven b the violent cathode bombardment either into or through the walls of the container. On the other hand, it frequently happens, b reason of overloads or other causes,'that e anodes and walls are overheated to such an extent that they 'give ofl excessive amounts of occluded gases, and the vacuum is lowered to a point where short-circuiting is liable to occur, with consequent extremely rapid liberation of gasm,

tainer 1.

In the normal operation of a rectifier of this character, the curernt flows alternately from the anodes 2 and 3 to the cathode 4 until the vacuum reaches such a high point that the arc becomes unstable. Under these conditions, by my invention, I first heat the cathode 4. by any suitable external means, such, for example, as a Bunsen burner 5, sufliciently to vaporize a mall portion of the mercury. By means of an ad ustable highpotential transformer 6, a high-potential discharge of considerable amperage is then caused to flow between the anodes 2 and 3 and through the current-conducting bodies evolved from the cathode. The high-potential electric discharge between the anodes 2 and 3 causes intense local heating thereof and serves to set free occluded gases there- Two from; thus lowing the vacuum to such a a point that the rectifier normal operation.

On the other hand, the vacuum in a bulb sometimes falls because the rate of gas liberation from the walls and anodes exceeds the normal rate of gas suppression. This is generall due to overloading or to improper treating-out in the manufacture of the bulb.

may be restored to I then proceed as in the previous case, heatvacuum is soon restored to normal.

: The time during j which the gas-control ling arc is applied to the bulb is also an important factor. 1 Generally speaking, the heavy-current discharge for Vacuum reduction should be applied for but a short time, whereas the small-current discharge for Vacuum raising should be maintained for a considerable period. With some tubes, in

order to obtain gas-suppressing action, it is necessary to use current of such amount that .the heating of the anodes approaches the gas-liberating point and it is then necessary to desist until the anodes have cooled. Furthermore, under certain conditions, I find that, with a given-current, there may be first a lowering of the vacuum and then a raising thereof. This action is apparently due to the fact that gases are first given off .by-

the portions of the anodes most directly exposed to the action of the discharge and this gas is subsequently absorbed by the ortions of the anodes which are less subject to the action of the discharge. By careful control of the time of discharge, therefore, it is possible-.toobtain nealjy any of vacuum.

I am aware that attempts have been made in the past to evolve gases from the electrodes of a rectifierby means of 'an extremelyhigh-potential electrical discharge.

My invention differs from this practice essentially ifu thefact that I employ a conducting bridge of material vaporized from the cathode for conveying the current from one electrode to the other. In the past, extremely high potentials have been impressed upon the defective bulb for the purpose of break- Frequently, the potential gradient is so steep near one of the anodes, as to cause the puncture of the container wall. 'I find that,

by connecting the cathode 4 to the mid point 7 of the secondary winding of the transformer through a high-resistance member 8, the potential strains within the container are distributed and puncture is avoided.

' In this specification and claims I am not using the term vacuum in its strict, absolute, physical meaning but rather in the relative sense commonly employed in this art.

Thus, to raise the vacuum implies merely exhaustion, and to lower the vacuum implies gas charging from any source ,whatever. I 1

have described my invention in. its preferred form, but it is obvious to those skilled in the art that it is susceptible of many changes and modifications, in degree and in manipulation, without departing from the spirit thereof. I desire therefore that no limitations shall be imposed except such as are set forth in the appended claims or are imposed by the prior art.

I claim las my invention? 1f The-method of aidin current flow be: tween two electrodes-wit in an evacuated container which comprises applying heat to an inactive pool of vaporizable material within said container.

2. The method of producing current flow between two anodes of a multi-anode vapor converter which comprises connecting a source of electromotive force between said anodes and heating the cathode without breaking down the negative-electrode reluctance thereof.

3. The method of producing a vacuum- "regulati wwtavithifi a" 'muitianode vapor-arc converter which comprises connecting a source of electromotive force across two anodes thereof and applying heat to the cathode.

.4- The method of regulating the vacuum in a vapor-arc converter which comprises producing a conductin vapor bridge there- .in between two electro es which are inactive with respect to each other during normal operation, and connecting a source of electromotive force therebetween, whereby a vacuum-regulating current is caused to flow.

5. The method of regulating the vacuum in a vapor-arc device which comprises producing a flow of current between two electrodes thereof, and adjusting the amount of said current flow by supplying carriers to the are path from a source' which'is adjustable independent of the current flowing in said arc. g

6. The method of raising, the vacuum in a multi-anode vapor converter which com-' prises producing a current flow between two anodes thereof of sufiiciently high voltage and small amperage to cause the elimination of gas particles from the arc space at a faster ratethan they are evolved from the electrodes, and adjusting the amount of current in said are by supplying the'arc path with carriers from an independently adjustable In testimony uary, 1915. I

HAROLD A. NEWCOMB.

Witnesses:

GoLDm E. McGee, B. B. Hnvns.

whereof, I have hereunto I subscribed my name this 29th day of Jan- 

